EFFECT OF SEWAGE SLUDGE ON BIOMASS PRODUCTION AND CONTENT OF MACRONUTRIENTS AND CHLOROPHYLL IN GRASS MIXTURES

The aim of this study was to determine the effect of various doses of municipal sewage sludge on the growth of biomass of aboveground parts of lawn grass mixtures and their macronutrients and chlorophyll content. Four experiments on the lawns along the main roads of Bialystok (at Popieluszki, Hetmanska, Piastowska and Raginisa Strs.) were founded. Three doses of sewage sludge (0.0 - control; 7.5 and 15.0 kg . m(-2)) and two grass mixtures: Eko and Roadside were factors in experiment. Samples of aboveground part of grasses were collected 3 times: in June, August and October 2011, after that dry matter of the aboveground part of grasses from 1 m 2, the total nitrogen content, total phosphorus content, total potassium content and chlorophyll a and b content were determined. The dose of sewage sludge significantly influenced N and K accumulation in the grasses. The maximum average nitrogen content (2.82 % of d. m.) was observed in grass from plots with the highest dose of sewage sludge, while the potassium from plots with sewage sludge dose 7.5 kg . m(-2). The accumulation of biomass of grasses in the study period was mainly differentiated by the sewage sludge dose and the sampling time. The average summary yield for the three months study (June, August and October) was from 229.83 to 430.70 g . m(-2). The highest results were obtained at a dose of sewage sludge 15.0 kg . m(-2). The sampling time and dose of sewage sludge significantly influenced chlorophyll a and b content. The average chlorophyll a content in June, August and October was: 0.60; 0.64 and 0.54 mg . g(-1) of f.m. respectively, while chlorophyll b: 1.00; 0.94; 0.39 mg . g(-1) of f.m. It was found a low average ratio of chlorophyll a to b in mixtures of grasses, which ranged from 0.54 in June to 1.82 in October to mixture Eco and 0.57 in June to 1.68 in October to mixture Roadside. Plants of the control plots showed higher average ratio of chlorophyll a to b in comparison with plants from plots with sewage sludge amendment.